Artificial Sweeteners Part III - Do They Cause Cancer?

One surefire way to start a debate is to make any statement about artificial sweeteners, whether it be in favor of or opposed to them. Let's take a moment to set aside our feelings on the matter and objectively look at the facts on some of the health claims made against artificial sweeteners. You can read part I here and part II here. Today we will investigate another claim made against artificial sweeteners.
(I am neither a registered dietitian nor a medical doctor. This should not be taken as dietary or medical advice. I am merely reading, interpreting, and summarizing the research for you.)

Some say artificial sweeteners cause cancer, but is it true?

Study: Life-Span Exposure to Low Doses of Aspartame Beginning during Prenatal Life Increases Cancer Effects in Rats

The experiment began 12 days into fetal life (12 days after the the conception of the test subjects). The aspartame was given via their mothers' feed. At 4-5 weeks old, the rats were weaned. 470 rats were selected, separated by sex, grouped by fives, and put into separate cages. 190 rats consumed 0 mg of aspartame per kg of body weight per day, 140 consumed ~20 mg/kg/day, and 140 consumed ~100 mg/kg/day. The rats were monitored from birth until death.

Results:
There was a 15.8% increase in the number of rats with tumors in the 100 mg/kg group and a 1.5% increase in the number of rats with tumors in the 20 mg/kg group compared with the group that received no aspartame. That means aspartame causes cancer, right?
No, not exactly.

How much is 100 mg/kg anyway? Let's use an average male at 190 pounds for an example. Consuming 100 mg/kg would equal 8,618.26 mg of aspartame in one day. That's 6.5 gallons of diet coke per day! (5.6 gallons for the average sized female)

Let's look at the 20 mg/kg for the same 190 pound male. This comes out to be 1.3 gallons of coke per day! (1.1 gallons for the average sized female) Don't forget, that also means you would have had to start this concentration of aspartame halfway through your mother's pregnancy, which is completely unrealistic.

Study: Aspartame: A Safety Evaluation Based on Current Use Levels, Regulations, and Toxicological and Epidemiological Studies [2]

This is the same review we looked at Friday. This review cites 149 studies.

Results:

This review states, "Extensive peer review and reevaluation of data and study protocols have occurred for several studies in different parts of the world. In all cases, the conclusions of the reviews by authoritative agencies and this panel have been that aspartame does not have carcinogenic or cancer-promoting activity. Furthermore, no toxic effect of aspartame that is relevant to humans consuming aspartame orally has been consistently demonstrated."

Study: Consumption of Aspartame-Containing Beverages and Incidence of Hematopoietic and Brain Malignancies [3]

This study examined 285,079 men and 188,905 women ages 50 to 71 years old in the NIH-AARP Diet and Health Study. Daily aspartame  consumption was derived from foods listed in the participants' food journals. The follow-up was done after five years (1995-2000). They grouped participants by dosage. The groups were as follows: 0 mg/d, 1-99 mg/d, 100-199 mg/d, 200-399 mg/d, 400-599 mg/d, and 600+ mg/d. 

Results:
First, I would like to note that the dosages in this study weren't assigned, they were observed in free-living individuals. The highest group was 600+ mg per day and was by far the smallest group. This implies that the average American consumes less than 600 mg per day, which is far from 8,618.26 mg. This study found that compared with zero consumption of aspartame, 600+ mg/d was not associated with any risk of overall hematopoietic cancer in men or women. Aspartame was also not associated with gliomas.

One interesting finding was that the study showed an association between aspartame intake and diabetes. Here's the important thing to catch though. People with increasing aspartame intakes were also more likely to have a more frequent history of smoking, to be less physically active, and have higher caffeine and Calorie intakes. I wanted to point this out to say it's important to look at the whole picture when talking about corrolation between two things. 

Takeaway 

I was only able to find one study that showed an association between aspartame intake and cancer rates and as I mentioned earlier, the dosage was just absolutely ridiculous. I'm fairly certain that even if it was physically possible, none of you would drink over six gallons of soda per day over the course of your life. I would consider the "aspartame causes cancer" myth to be busted. 

That's all for this time. Join me next week for another area of health as it relates to aspartame intake. God bless you AND your family! I'll catch you next time.

References:

[1] Soffritti, M., Belpoggi, F., Tibaldi, E., Esposti, D. D., & Lauriola, M. (2007). Life-Span Exposure to Low Doses of Aspartame Beginning during Prenatal Life Increases Cancer Effects in Rats. Environmental Health Perspectives115(9), 1293–1297. http://doi.org/10.1289/ehp.10271
[2] Magnuson, B. A., Burdock, G., Doull, J., ... Williams, G. (2007). Aspartame: A Safety Evaluation Based on Current Use Levels, Regulations, and Toxicological and Epidemiological Studies. DOI: 10.1080/10408440701516184
[3] Lim, U., Subar, A. F., ... Schatzkin, A. (2006). Consumption of Aspartame-Containing Beverages and Incidence of Hematopoietic and Brain Malignancies. American Association for Cancer Research, 15(9), 1654-1659. https://doi.org/10.1158/1055-9965.EPI-06-0203